A QoS provisioning framework for cognitive radio network

• Main Author: Vishram Mishra
• Other Authors: Lau Chiew Tong
• Format: Theses and Dissertations
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems; DRNTU::Engineering::Computer science and engineering::Computer systems organization::Computer-communication networks
• Online Access: http://hdl.handle.net/10356/62316
• Institution: Nanyang Technological University

The free usage of spectrum by cognitive radio user on a non-interfering policy basis is anticipated to make it prominent as a candidate for backbone communication in devices utilizing wireless channels for communication purposes. Since today’s portable devices are capable of handling multimedia content delivery over wireless channels, quality of service (QoS) is an important factor to provide a guarantee on assured level of services to multimedia and real time applications. The QoS is broadly defined for two parameters of the wireless networks: throughput and latency. Different attributes in wireless network are responsible for providing QoS with different levels of participation contributing to the throughput and latency perspective of the quality of service. We have proposed a QoS framework for cognitive radio network, which identifies and divides attributes of system into different modules responsible for quality of service. These modules are independently studied and a relation between them is shown to depict the interaction between these modules. These modules are responsible for channel selection, media access control, self-coexistence and energy saving. A relationship is drawn among these modules for a coherent decision followed by the system. The framework supports four access categories for service differentiation. The framework is also designed in such a way that it separates main communication protocol stack from quality of service engine and thus allows its support for legacy protocol stack with minimal variation. We have developed three different spectrum selection schemes for deterministic channel environment along with a spectrum selection scheme for stochastic channel environment. The schemes in deterministic channel environment utilize the deterministic pattern of the channel availability to make a decision on the selection of channels, allowing the system to make decision ahead of the actual decision time. Whereas, the channel selection scheme for stochastic channel environment utilizes a tabular mapping to map packets to different categories of channels, allowing faster spectrum decision and low complexity of the system. A spectrum decision scheme from the perspective of energy management is also proposed which select channels requiring minimal energy for transmission while implementing a packet admission control scheme to allow service differentiation. The proposed scheme saves considerable amount of energy while providing quality of service support to high priority applications. A media access control scheme is developed to support four different access categories while supporting power saving mode operation, and network operations of multicast and broadcast. The proposed access scheme is also shown to solve the problem of multi-channel hidden terminal. Two different methods of self-coexistence for multiple cognitive radio networks have been developed from the perspective of resource relocation and resource sharing. For resource relocation, a multi-coloring scheme has been proposed along with a formal relationship between the optimization problems of resource allocation and graph coloring. A superframe sharing based approach has been proposed for resource sharing based self-coexistence technique. Both of these scheme for self-coexistence in cognitive radio network have been shown to support quality of service along with fairness to individual users operating in the system.